Every neighboorhood has different reasons for them. How many kids are out there playing? Any elderly couples walking often? Speed bumps are not a bad idea unless someone enjoys flying thru a residential neighborhood,close to the cars on the streets. Is there a problem with people speeding? Another thing speedbumps do is curtail the habit of non-residents using you streets as a pass thru to another main road. Bad thing about them is low laying exhaust on cars. I creep real slow over them in my car.Stop with the front wheels on them as I approach,climb the front tires over,slow down and get the rears over. Nice and easy. I have turned around before instead of attempting some. They also have the hard plastic type that secure to the roadway without having to pile asphalt on the road. Plus they seem to have an angled approach and drop on them,a little smoother on you.